In antenna technology it is important to provide suitable means to modify the electrical characteristics or performance of an antenna to adapt the antennas performance to the operating environment. Typical modifiable antenna characteristics include but are not limited to antenna aperture, operating frequency and bandwidth, directionality and gain, radiation pattern and impedance matching, voltage standing wave ratio (VSWR), as well as antenna power handling capability. Some methods to modify antenna performance have included changing the geometry of the radiating element, adding capacitive hats, selectively connecting multiple antennas or antenna elements, using different materials, and the like. One way to modify antenna characteristics is to employ a liquid metal such as mercury in an enclosed chamber. When heated or cooled, the mercury expands or contracts within the chamber. Because of its low interfacial resistance and high conductivity, the mercury can act as an antenna radiating element that can have its frequency range varied by varying its temperature. However, mercury is a well-known biological hazard, making it unsuitable for commercial use.
It is therefore an object of the invention to provide a variable frequency antenna.
Another object of the invention is to provide a variable frequency antenna using a non-hazardous liquid metal.
A feature of the invention is the use of a gallium-based alloy in liquid form at ambient temperatures as a variable-length radiating element in an antenna.
An advantage of the invention is that the gallium-based alloy is environmentally and biologically safe to handle and use.
Another advantage is that a single liquid-metal antenna can be modified for use over a variety of frequencies by heating and cooling the liquid metal.